Stephanie Burkhardt is one of the luckier members of a group no one wants to join: She’s the mother of a child with a rare, incurable disease.
When her son Connor was 3, he started having unexplained seizures. Testing at Children’s Hospital Colorado quickly uncovered the cause — a genetic syndrome called Batten disease, which causes waste products to build up in his cells.
Children with Batten disease either don’t meet developmental milestones, or lose skills over time. They eventually lose their sight and ability to speak or move, and have a shortened life expectancy. The disease has 13 subtypes, which affect about 14,000 children worldwide.
While the diagnosis was devastating, getting it quickly allowed Connor, now 6, to promptly start receiving a drug that reduces his seizures and allows him to attend school and play around their Centennial home like a boy who isn’t sick, Burkhardt said. Most children with Batten disease aren’t able to feed themselves, speak or move under their own power by that age, so while Connor still will have a shorter life, he’s getting to enjoy it, she said.
“Our experience was really smooth, which is not the norm,” Burkhardt said.
Children’s is trying to make the process of diagnosing and treating rare diseases easier for more families, said Dr. Scott Demarest, clinical director of the hospital’s Precision Medicine Institute. The institute isn’t a clinic that patients can schedule an appointment with, but a sort of support system for providers caring for kids with genetic conditions. The in-house lab is working to expand how much information it can draw from patients’ genes, he said.
Precision medicine is an umbrella term for treatment based on a person’s genetics. In recent years, it’s notched notable successes around the world, including treatments that:
Take out a gene that caused misshapen proteins to build up to destructive levels in the rare disease amyloidosis
Reprogram cells to perceive light to partially restore vision in a blind person
Turn on the ability to make a healthy form of hemoglobin, possibly curing some people with sickle cell disease
The treatments can cost millions, though, and sometimes come with grueling side effects.
The Precision Medicine Institute’s staff is also working to prepare Children’s Hospital to give those types of new therapies for genetic conditions, which offer “exciting” results but also carry higher risks, Demarest said.
For example, some therapies use a harmless virus to deliver a healthy gene to someone with a life-threatening mutation, but there’s always a small possibility that the body will react badly to the virus. There’s no system to notify doctors about adverse events with gene therapy, so closely monitoring results from other hospitals will be part of the team’s job, he said.
“If there’s ever (a problem) that’s preventable, we want to make sure we’re preventing it,” he said.
Demarest estimated 5,000 to 6,000 patients might be served by the Precision Medicine Institute in a typical year.
For the first few decades of genetic testing, it was only possible to look for specific genes known to be important, but now it’s become relatively affordable to read all the “letters” that make up someone’s genes, Demarest said. The next step is to read all the instructions surrounding the genes, which turn them on and off and help guide the body in making its proteins, he said.
It’s comparable to going from a list of ingredients to being able to see the full recipe, since the letters make up only about 3% of someone’s genetic material, Demarest said. Some studies estimate that the increased detail could mean an additional 10% of people with genetic conditions receive a diagnosis, he said. Currently, less than 60% learn what caused their condition.
People may not get clear answers immediately, though. If you decode the letters of an average person’s DNA, you’ll typically find about 1,000 unexpected differences from the standard genome, but almost none of them turn out to be important, Demarest said. It’s likely most people will also have some differences in the instructions surrounding their genes, but it will take data from a large number of patients to sort out which are benign and which cause disease, he said.
“We’re just scratching the surface on how to interpret that non-coding DNA and use that for clinical care,” he said.
While many patients won’t have a treatment available even if the testing does find a cause, the information can still be valuable for families who are trying to decide whether to have another child or who blame themselves for their child’s condition, Demarest said.
“That at least tells us the why,” he said.
Burkhardt said having an answer not only allowed her family to get Connor treatment that improved his quality of life, but also helped lay out a path for them to have a second child. She and her husband had always wanted two children, but didn’t want to risk passing Batten disease on again, she said. They opted to pursue in vitro fertilization, which allows for genetic testing of embryos, and had a healthy son earlier this summer.
“There’s so much we’ve been given as a rare disease family,” she said.
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